THURSDAY, June 3 (HealthDay News) -- Four out of five poker players use any one of a number of legal and illicit drugs to improve their game, a new study suggests.

Researchers from Nova Southeastern University (NSU) in Fort Lauderdale, Fla., found that alongside caffeine, energy drinks and guarana, professional and amateur players all over the world are turning to marijuana, cocaine, amphetamines, Valium and a host of other prescription medications to try to gain some advantage at the table.

"The use of these substances could allow poker players to stay awake longer, as well as focus and concentrate better, which would be a competitive advantage, study author Kevin Clauson, an associate professor at NSU's College of Pharmacy, said in a university news release.

"Stamina is important for any poker player because tournament poker and cash games can go on for many hours," he added.

The observation stems from interviews conducted in Las Vegas during the World Series of Poker tournament, as well as from an internal survey of professional, semi-professional, amateur and recreational players in North America, Europe and Asia, that was conducted online.

Most of the survey participants were men in their mid-20s, the majority of whom played the "no-limit Texas hold 'em" version of poker. Most also said the games they played involved a cash payout of some kind.

About three-quarters of those surveyed said they used some kind of drug or substance to improve their focus and concentration, while the remaining users said they were seeking a way to calm their nerves, avoid fatigue and sharpen their memory.

"Most people we surveyed are using some kind of a boost in order to play one of the most popular games in the world," noted Clauson.

The findings were presented recently at the Psychiatric & Neurologic Pharmacists annual meeting in San Antonio.